Japanese Utility Model Application Laid-open No. 56-56143 discloses an engine oil surface level detection apparatus. This level detection apparatus is described below with reference to FIG. 12.
The level detection apparatus 200 shown in FIG. 12 is composed of a housing 201 whose lower portion is open, a shaft 203 that extends downward so as to be suspended from the ceiling 202 of the housing 201, a float 204 that is slidably mounted on the shaft 203, a magnet 205 provided to the float 204, a reed switch 206 housed in the shaft 203 and actuated by the approach of the magnet 205, cylindrical bushes 208 and 208 mounted on the opening formed in the side walls 207 and 207 of the housing 201, and a crankcase for holding engine oil 209.
However, in the level detection apparatus 200, the side walls 207 and 207 of the housing 201 are open by way of the cylindrical bushes 208 and 208. Therefore, the surface level of the oil is susceptible to transient fluctuations when the engine oil 209 in the crankcase is lifted up.
Wiring is furthermore laborious in that wires must be laid out in the oil in order to draw out the wires of the reed switch 206.
In view of the above, there is a need for an engine oil-level detection apparatus that can avoid being susceptible to fluctuations in the surface level of the oil and that can simplify the procedure for drawing out wires from a switch.